CF231A Team

## 题目要求 三位选手要去参加编程竞赛，比赛共有N道题目，他们商定: 对于每一道题目，只有两位及以上的选手确认找到解法时才做。 试问，他们一共能做多少题?

第一行一个整数N，表示题目的数量。 第二行到第N+1行，每行三个整数(0或者1)，其中0表示这位选手无法解出此题，1表示这位选手想到了解法。

一行，一个整数，表示他们所能做的题目的数量。 感谢@PC_DOS 提供翻译

In the first sample Petya and Vasya are sure that they know how to solve the first problem and all three of them know how to solve the second problem. That means that they will write solutions for these problems. Only Petya is sure about the solution for the third problem, but that isn't enough, so the friends won't take it. In the second sample the friends will only implement the second problem, as Vasya and Tonya are sure about the solution.